Internal combustion engines



R..E. GEORGES INTERNAL COMBUSTION ENGINES Feb. 19, 1963 2 Sheets-Sheet 1Filed Jan. 16, 1961 Feb. 19, 1963 R. E. GEORGES 3,0

INTERNAL COMBUSTION ENGINES Filed Jan. 16, 1961 2 Sheets-Sheet 23,ti77,868 INTERNAL C(PMBUSTION ENGINE? Raymond Emile Georges, 67 AvenueFoch, Paris, France Filed Jan. 16, 1.961. Ser. No. 83,608 8 Claims. (Cl.123-32) The present invention relates to reciprocating piston internalcombustion engines, and more particularly all such engines irrespectiveof their cycle of operation.

The invention is more especially but not exclusively concerned withengines of the above type having a constant pressure cycle, that is tosay operating by direct injection of fuel, such as in diesel engines.

It is known to provide engines of the above kind with a main combustionchamber in permanent communication, through a transfer passage ofadjustable cross section area, with an auxiliary combustion chamber towhich fuel is delivered directly by at least one fuel injection device.

The object of the present invention is to provide an engine of the lastmentioned kind which is better adapted to meet the requirements ofpractice than those known, in particular concerning the operation of themeans for adjusting the cross section area of the transfer passage.

According to the present invention, the transfer passage communicateswith a chamber, hereinafter called prechamber interposed between saidtransfer passage and the auxiliary combustion chamber and a plunger,preferably made of a refractory material, is adapted to cooperate withthis prechamber, this plunger being slidable with respect to saidprechamber between two positions, a retracted one for which the smallestcross section area of flow gas through said prechamber is at least equalto the cross section area of said passage, and a projecting one forwhich the smallest cross section area of flow through said prechamber issmaller than the cross section area of said passage.

Preferred embodiments of the present invention will be hereinafterdescribed with reference to the accompanying drawings, given merely byway of example and in which:

FIG. 1 is an axial sectional view of an internal combu-stion engineaccording to a first embodiment of the invention.

FIG. 2 shows a modification of the embodiment of FIG. 1 and particularlyof the means for controlling the position of the plunger.

FIG. 3 is an axial sectional view of an internal combustion engineaccording to a second embodiment of the invention.

In the following description, it will be assumed that the engine is ofthe constant pressure cycle type.

According to FIG. 1 there is shown a cylinder 1 in which a piston 2 issliclably fitted. Piston 2 defines with the corresponding portions of acylinder head 3, a main combustion chamber A. I

Moreover, an auxiliary chamber B is provided in said cylinder head 3 andin permanent communication with said main chamber A through a transferpassage 4. Fuel is injected into auxiliary chamber B through aconventional injector 5 preferably mounted in such manner that it can beadjustably engaged in said auxiliary chamber, so as to make it possibleto vary the volume thereof, for instance if another fuel is to be usedin the engine.

The mass and dimensions of the movable parts of this engine aredetermined in such manner that it is of a light type and capable ofworking with a high piston velocity and a high number of revolutions perminute, as compared to conventional diesel engines.

It is known that, in order to avoid fatigue failures of the relativelylight weight movable parts of this engine, especially during theexpansion stroke, it is necessary to provide means for varying the flowrate of the gaseous streams from the main combustion chamber A towardthe auxiliary combustion chamber B or vice versa.

For this purpose, it is known to provide the transfer passage betweenchambers A and B with a portion of adjustable cross section area adaptedto be controlled by a movable closing device including surfaces infrictional contact with each other so as to permit adjusting the crosssection of said portion.

This solution involved relative displacements of parts in frictionalcontact with one another while they are subjected to the action of gasesat high temperatures. In such conditions, there were risks of seizingand of impairing the gastightness of the main closing means. The chiefobject of the present invention is to obviate this drawback, that is tosay to permit controlling the flow rate of the gas stream circulatingbetween chambers A and B without making use of parts in frictionalcontact with one another.

According to the present invention, there is provided in cylinder head3, between transfer passage 4 and auxiliary combustion chamber B, aprecharnber 6 serving to connect said passage 4 with said chamber B. Inthis prechamber 6 there is provided at least one plunger 7 oppositepassage 4 and slidable in said chamber, between a retracted and aprojecting position. In the retracted position, the minimum crosssectional area for the flow of the gas stream through prechamber 6 is atleast equal to the cross sectional area of passage 4. For the projectingposition of. plunger 7, the minimum cross sectional area for the flowthrough chamber 6 is smaller than the cross section of passage 4.

It will thus be possible to dimension transfer passage 4 in such mannerthat its cross sectional area corresponds substantially to an optimumvalue such that under conditions of operation fatigue failure of themovable parts of the engine is minimized and the flow rate of the gasstream through said passage 4 is reduced by bringing plunger 7 into anat least partly projecting position when the conditions of operation aresuch that an overload on the movable parts .of the engine is to befeared, in particular due to the duration of the time of transferbetween chambers A and B.

On the other hand, control of the gas exchange between the two abovementioned chambers takes place without any contact between plunger 7 andthe walls of the cylinder head structure directly exposed to the actionof the gaseous flux, which eliminates any risks of seizing or ofalteration of said walls.

Preferably, plunger 7 is made of a material having a high resistance toheat, for instance a refractory alloy or graphite.

Gastightness is advantageously obtained by providing the movable systemto which plunger 7 proper belongs with two closing members 8 and 9adapted to be applied respectively against bearing surfaces 10 and 11according as said plunger 7 is in retracted position (member 8 being incontact with bearing surface 10) or in projecting position (member 9being in contact with bearing surface 11) as shown by FIG. 1.

Thus the means for guiding plunger 7, which may consist for instance ofcylindrical bearing means 12 slidable in a bore 13 provided in a portionof cylinder head 3 is isolated in a gastight manner when the plunger isin one of its end positions, either by member 8 when the plunger isretracted or by member 9 when the plunger is projecting.

Advantageously, as shown, transfer passage 4 and plunger 7 are in linewith each other and substantially parallel to the axis of cylinder 1,the axis of auxiliary chamber B being perpendicular .to said axis.

Advantageously, as shown, the means for controlling plunger 7 is suchthat this plunger is urged toward its retracted position by a spring 14whereas control means consisting of a cam 15 is capable of bringingplunger 7 into its projecting position.

Cam 15 may be operated manually by the driver when the workingconditions of the engine require a reduction of the transfer flow ratebetween chambers A and B. Automatic means responsive to variations of afactor of operation of the engine, for instance tachometric governingmeans, may also be used to move plunger 7 in the retracting directionwhen the speed of the engine increases above a given value.

Plunger 7 may also be moved into active position on every cycle of theengine. In this case, the plunger must be brought into active positionwhen the force exerted on piston 2 is maximum that is to say when saidpiston is close to its upper dead center position during everycompression stroke thereof, said plunger remaining in retracted positionduring the remainder of the cycle.

For this purpose, as shown by FIG. 2, plunger 7 is operatively connectedwith means operating the valves of the engine, for instance through anadjustable threaded rod 16a and a lever 16 controlled by a cam 15adriven at a speed equal to one half of that of the engine, said cambeing adjusted so that the plunger is brought into projecting positionduring every above mentioned period of the cycle.

The engine above described may further include means for cyclicallyinjecting high pressure compressed air into prechamber 6 to enrich thegaseous streams with oxygen during the expansion stroke, such meansconsisting, as shown, of an automatic valve 17 disposed in a compressedair conduit 18.

It should be noted that such an engine is well adapted for use withdifferent fuels, especially when auxiliary chamber B is made of variablevolume for instance by adjustably engaging piston 19, forming a supportfor injector into said chamber B. The position of piston 19 iscontrolled in accordance with the characteristics of the fuel that isused.

FIG. 3 shows another embodiment of the invention including various otherfeatures. In FIG. 3 the elements corresponding to those alreadydescribed with reference to FIG. 1 are designated by the same referencenumerals.

In the engine of FIG. 3, plunger 7 is arranged in such manner that itsbody has a cross sectional area smaller than that of the end thereoflocated opposite transfer passage 4, the latter said end being forinstance in the form of a portion of a sphere.

For this purpose, as shown in solid lines, the body 7a of plunger 7 is,in the form of a rod having a circular cross section of a radius muchsmaller than that of the end portion of the plunger.

Additionally, as shown in dot and dash lines (with indication of thecross section), said body 7a may be provided with a streamlined crosssectional shape to limit the resistance to fiow of the gas streams. Theshape may be of an elongated airfoil contour.

In both cases the reduced portion 7a of the plunger is connected throughrounded lines wth the end of said plunger. This construction makes itpossible to obtain an increased power due to the corresponding increasein volume of prechamber 6 and to the increase of temperature of thewhole of the plunger, this increase of temperature reducing thecondensation of fuel on the plunger and accelerating vaporization.

According to another feature, cylinder head 3, which is made ofaluminium or a light alloy, is provided with an inner lining 3a of amaterial capable of maintaining its mechanical resistance qualities athigh temperature, for instance a refractory metal or an austeniticsteel.

The valve seats and the orifice intended to receive transfer passageconduit 4 are directly machined in this lining.

Advantageously also, prechamber 6 is provided with a similar metallining.

The lining 3a of cylinder head 3 and the lining 6a of prechamber 6 maybe threadably fixed in said cylinder head.

According to still another feature, the means 20 for controlling thedepth of en agement of the support 21 of injector 5 to determine thecompression ratio of the engine is located on the outside of cylinderhead 3 to avoid dangerous heating thereof.

According to still another feature, the end of the support 21 ofinjector 5 is in the shape of a flaring nozzle or diffuser 21a extendingfrom the outlet of the injector. Preferably the outer wall of nozzle21:: is recessed so as to form a space 22 where air can accumulate andwhich space communicates through a calibrated passage 23 with prechamber6 and through channels 24, extending radially and preferably inclined inthe direction of the jet, with the inside of diffuser 21a.

This arrangement produces a sweeping of the burnt gases which wouldotherwise tend to remain in the vicinity of the injector.

According to a still further feature of the invention, transfer passage4 has its outlet into main chamber A directed toward the reserves of air(dead spaces) existing in said chamber, especially in the portionthereof where the valves are located, the transfer passage beingpreferably formed, as shown, in a piece 25 made of a refractory materialand adapted to be rotatably adjustable when mounted in its housing.

In a general manner, while I have, in the above description, disclosedwhat I deem to be practical and efficient embodiments of my invention,it should be well understood that I do not wish to be limited thereto asthere might be changes made in the arrangement, disposition and form ofthe parts without departing from the principle of the present inventionas comprehended within the scope of the accompanying claims.

What I claim is:

1. An internal combustion engine which comprises, in combination, acylinder, a piston slidably supported in said cylinder for reciprocatingmovement therein, a cylinder head defining with said piston, at the endof every inward stroke thereof in said cylinder, a main combustionchamber, means defining an auxiliary combustion chamber fixed withrespect to said cylinder, means for injecting fuel into said auxiliarycombustion chamber, means fixed with respect to said auxiliarycombustion chamber forming a prechamber in permanent communication withsaid auxiliary combustion chamber, means fixed with respect to saidprechamber and said cylinder forming a permanently open transfer passagebetween said prechamber and said main combustion chamber, a plungersupported in said prechamber forming means and movable with respectthereto between limit positions, one of said positions being a retractedposition, the other being a projecting position, said plunger in saidpositions defining a path in said prechamber for the flow of fueltherethrough, said path having a minimum cross sectional area with theplunger in the retracted position which is at least equal to the crosssectional area of the passage, said path having a minimum crosssectional area with the plunger in the projecting position which is lessthan the cross sectional area of said passage, and means operative fromoutside said cylinder for controlling the active position of saidplunger with respect to said prechamber.

2. An internal combustion engine according to claim 1. furthercomprising means operatively connected with said piston for actuatingsaid plunger to move the same to said projecting position at the end ofevery compression stroke of the engine.

3. An internal combustion engine which comprises, in

combination, a cylinder, 2. piston sliclably supported in,

said cylinder for reciprocating movement therein, a cylinder headdefining with said piston, at the end of every inward stroke thereof insaid cylinder, a main combustion chamber, means forming an auxiliarycombustion chamber fixed with respect to said cylinder, means forinjecting fuel into said auxiliary combustion chamber, means forming aprechamber fixed with respect to said auxiliary combustion chamber andin permanent communication therewith, means fixed with respect to saidprechamber and said cylinder and providing a permanently open transferpassage between said prechamber and said main combustion chamber, and aplunger slidable in said prechamber between two positions, one of saidpositions being a retracted one for which the smallest cross sectionalarea for the fiow of fuel through said prechamber is at least equal tothe cross sectional area of said passage, the other of said positionsbeing a projecting one for which the smallest cross sectional area forthe fiow of fuel through said prechamber is smaller than the crosssectional area of said passage, said plunger including a body located insaid prechamber and including an end located opposite said transferpassage and of a cross section greater than that of said transferpassage, said body including a remaining portion of a cross sectionsmaller than that of said end.

4. An internal combustion engine according to claim 3, in which saidremaining portion of said body is of circular cross section of a radiussubstantially smaller than that of the cross section of said plungerend.

5. An internal combustion engine according to claim 3, wherein said fuelinjecting means is adapted to direct fuel along an axis into saidprechamber, said remaining portion of said body having a cross sectionin planes parallel to said axis which is smooth and elongated in thedirection of said axis to minimize resistance to fiow of said fuel.

6. An internal combustion engine which comprises, in combination, acylinder, a piston slidably supported in said cylinder for reciprocatingmovement therein, a cylinder head defining with said piston, at the endof every inward stroke thereof in said cylinder, a main combustionchamber, means forming an auxiliary combustion chamber fixed withrespect to said cylinder, means for injecting fuel into said auxiliarycombustion chamber, means fixed with respect to said auxiliarycombustion chamber forming a prechamber in permanent communication withsaid auxiliary combustion chamber, means fixed with respect to saidprechamber and said cylinder forming a permanently open transfer passagebetween said prechamber and said main combustion chamber, a plungersupported by said prechamber forming means and movable with respectthereto between limit positions, one of said positions being a retractedposition, the other being a projecting position, said plunger in saidpositions defining a path in said prechamber for the flow of fueltherethrough, said path having a minimum cross sectional area with theplunger in the retracted position which is at least equal to the crosssectional area of the passage, said path having a minimum crosssectional area with the plunger in the projecting position which is lessthan the cross sectional area of said passage, said prechamber formingmeans being provided with a cylindrical bore in line with the opening ofsaid transfer passage in said prechamber, a rod slidably supported insaid bore and coupled to said plunger to control the position thereof,said prechamber forming means including two fixed annular bearingsurfaces locataed respectively at the opposite ends of said bore, andannular parts on said rod and constituting two annular bearing surfacesfor cooperating in gastight fashion with one of said two fixed annularbearing surfaces, respectively with said plunger in said retracted andprojecting positions.

7. An internal combustion engine which comprises in combination, acylinder, a piston slidably supported in said cylinder for reciprocatingmovement therein, a cylinder head defining with said piston, at the endof every inward stroke thereof in said cylinder, a main combustionchamber, means forming an auxiliary combustion chamber fixed withrespect to said cylinder, means for injecting fuel into said auxiliarycombustion chamber, means fixed with respect to said auxiliarycombustion chamber forming a prechamber in permanent communication withsaid auxiliary combustion chamber, means fixed with respect to saidprechamber and said cylinder forming a permanently open transfer passagebetween said prechamber and said main combustion chamber, a plungersupported by said prechamber forming means and movable with respectthereto in between limit positions, one of said positions being aretracted position, the other being a projecting position, said plungerin said positions defining a path in said prechamber for the fiow offuel therethrough, said path having a minimum cross sectional area withthe plunger in the retracted position which is at least equal to thecross sectional area of the passage, said path having a minimum crosssectional area with the plunger in the projecting position which is lessthan the cross sectional area of said passage, and means operative fromoutside of said cylinder for controlling the position of said plungerwith respect to said prechamber, the axis of said transfer passage andthe line along which said plunger is slidable being coincident and beingparallel to the cylinder axis, said auxiliary combustion chamber havingits axis at right angles to the cylinder axis.

3. An internal combustion engine which comprises, in combination, acylinder, a piston slidably supported in said cylinder for reciprocatingmovement therein, a cylinder head defining with said piston, at the endof every inward stroke thereof in said cylinder, a main combustionchamber, means forming an auxiliary combustion chamber fixed withrespect to said cylinder, means for injecting fuel into said auxiliarycombustion chamber, means fixed with respect to said auxiliarycombustion chamber forming a prechamber in permanent communication withsaid auxiliary combustion chamber, means fixed with respect to saidprechamber and said cylinder forming a permanently open transfer passagebetween said prechamber and said main combustion chamber, a plungersupported by said prechamber forming means and movable with respectthereto between limit positions, one of said positions being a retractedposition, the other being a projecting position, said plunger in saidpositions defining a path in said prechamber for the flow of fueltherethrough, said path having a minimum cross sectional area with theplunger in the retracted position which is at least equal to the crosssectional area of the passage, said path having a minimum crosssectional area with the plunger in the projecting position which is lessthan the cross sectional area of said passage, means operative fromoutside of said cylinder for controlling the position of said plungerwith respect to said prechamber, a support for said fuel injecting meansand a flaring nozzle on said support and constituting a diffuser, saidnozzle being coupled to said fuel injecting means and opening into saidprechamber, said nozzle including an outer wall defining an annularspace therearound, said outer wall defining a calibrated passageseparating said space and said prechamber, said wall being provided withradial passages to permit said space to communicate interiorly of saidwall.

References Cited in the file of this patent UNITED STATES PATENTS2,198,979 Schwaiger Apr. 30, 1940 FOREIGN PATENTS 673,149 France Jan.10, 1930 992,440 France July 11, 1951

1. AN INTERNAL COMBUSTION ENGINE WHICH COMPRISES, IN COMBINATION, ACYLINDER, A PISTON SLIDABLY SUPPORTED IN SAID CYLINDER FOR RECIPROCATINGMOVEMENT THEREIN, A CYLINDER HEAD DEFINING WITH SAID PISTON, AT THE ENDOF EVERY INWARD STROKE THEREOF IN SAID CYLINDER, A MAIN COMBUSTIONCHAMBER, MEANS DEFINING AN AUXILIARY COMBUSTION CHAMBER FIXED WITHRESPECT TO SAID CYLINDER, MEANS FOR INJECTING FUEL INTO SAID AUXILIARYCOMBUSTION CHAMBER, MEANS FIXED WITH RESPECT TO SAID AUXILIARYCOMBUSTION CHAMBER FORMING A PRECHAMBER IN PERMANENT COMMUNICATION WITHSAID AUXILIARY COMBUSTION CHAMBER, MEANS FIXED WITH RESPECT TO SAIDPRECHAMBER AND SAID CYLINDER FORMING A PERMANENTLY OPEN TRANSFER PASSAGEBETWEEN SAID PRECHAMBER AND SAID MAIN COMBUSTION CHAMBER, A PLUNGERSUPPORTED IN SAID PRECHAMBER FORMING MEANS AND MOVABLE WITH RESPECTTHERETO BETWEEN LIMIT POSITIONS, ONE OF SAID POSITIONS BEING A RETRACTEDPOSITION, THE OTHER BEING A PROJECTING POSITION, SAID PLUNGER IN SAIDPOSITIONS DEFINING A PATH IN SAID PRECHAMBER FOR THE FLOW OF FUELTHERETHROUGH, SAID PATH HAVING A MINIMUM CROSS SECTIONAL AREA WITH THEPLUNGER IN THE RETRACTED POSITION WHICH IS AT LEAST EQUAL TO THE CROSSSECTIONAL AREA OF THE PASSAGE, SAID PATH HAVING A MINIMUM CROSSSECTIONAL AREA WITH THE PLUNGER IN THE PROJECTING POSITION WHICH IS LESSTHAN THE CROSS SECTIONAL AREA OF SAID PASSAGE, AND MEANS OPERATIVE FROMOUTSIDE SAID CYLINDER FOR CONTROLLING THE ACTIVE POSITION OF SAIDPLUNGER WITH RESPECT TO SAID PRECHAMBER.